At least three anti-government protesters were killed and 300 were injured by gunshot and tear gas when police stormed a sit-in in the Yemeni capital of Sanaa on Saturday, according to medics and a Xinhua correspondent at the scene.

Around five thousand of policemen in protective gear advanced on a sit-in of approximately 100,000 protesters demanding the immediate resignation of President Ali Abdullah Saleh who has ruled the country for 33 years outside Sanaa University, killing at least three protesters, according to eyewitnesses.

About 300 protesters were injured by tear gas and gunshot, the eyewitness said.

Twfic al-Yazidy, an architect at the scene, told Xinhua that " the police who used live bullets and tear gas failed to break up the rally as protesters managed to repel the attack by keeping shouting 'we are peaceful, peaceful'."

Another eyewitness named Hamoud Hazza said the police still fired to the air as water cannon vehicles were deployed along with more police cars carrying more riot policemen for an apparent attempt to disperse the protesters.

Electricity was cut off as streets leading to the scene were blocked after police put the sit-in under a tighten siege, several eyewitnesses said.

On Tuesday, one protesters of Sanaa camp was shot dead during clashes with police while more than 70 others suffered suffocation of tear gas.

Saleh have repeatedly asked the government to protect the demonstrations. Inspired by Tunisian and Egyptian protests, protesters in Yemen have staged daily mass rallies since mid February calling for Saleh's resignation.